Meanwhile, a US district court in New York is hearing a suit brought on behalf of more than 200 Haitians being held at the Guantanamo Bay naval base in Cuba. These detainees were pre-screened for political asylum and would have been allowed to enter the US had they not tested positive for HIV, the virus that is associated with AIDS. Their lawyers contend that the Haitians' medical condition is not grounds for nullifying US laws that require asylum claims to move forward.

Asylum claims hinge on the ability of refugees to persuade US officials interviewing them that threats to life and freedom forced their flight from their native countries. If pre-screening shows that an asylum seeker has a "credible" fear of persecution, further screening is undertaken to establish that the fear is "well-founded." According to US and international law, people asking for asylum cannot simply be sent back to the lands they fled.

The Haitian cases now before US courts touch on a dilemma that affects many countries and is likely to deepen in the years ahead: How to abide by international legal obligations to protect people who are fleeing persecution (obligations incorporated in US immigration law) while allaying domestic political concerns about losing control of national borders.

Those championing the Haitians' asylum claims view the cases as a test not only of Washington's willingness to abide by its own laws, but also of the country's ability to live up to its humanitarian ideals. The government's position, on the other hand, is that US immigration law allows the president emergency powers to suspend regular procedures when faced with a "mass invasion of foreigners."

That position is backed by politicians and lobbying groups who perceive a breakdown in the US immigration system. "The whole asylum policy and law is simply corrupted," says Daniel Stein, head of the Federation for American Immigration Reform (FAIR). He decries what he says are politically motivated distortions that give certain groups, notably Cubans, easier asylum than others and a disproportionate share of the yearly refugee quota.

Mr. Stein argues further that US political leaders have yet to come to terms with the large numbers of people who want to enter the country today.

ALTHOUGH the US sets a yearly cap on the number of refugees who are formally processed abroad and then admitted (132,000 in fiscal year 1993), there are no limits on the number of people who can apply for political asylum, a different procedure that normally takes place in the US itself. The Immigration and Naturalization Service has seven locations where such applicants are interviewed, says Vernon Jervis, chief of the INS press office, and it has a backlog of more than 200,000 applicants.

"We're seeing immigration of a magnitude that we haven't seen since the Irish potato famine," Mr. Stein says.

Those who back the Haitians' claims for asylum say such concerns distort the fundamental legal issues. "In relative terms, the numbers of Haitians are small," says Arthur Helton, director of the Refugee Project for the Lawyers' Committee for Human Rights. "It's a more complicated question of sovereignty, [national] prerogatives, and a general anti-alien environment."

Washington views the Haitians as an immigration problem, says Johnny McCalla, who directs the New York-based National Coalition for Haitian Refugees. In fact, he argues, they represent an emergency refugee-protection problem, and the laws are in place to deal with it. Mr. McCalla says nearly one-third of the Haitians interviewed have been granted protection in the US.

The Haitian plaintiffs are being represented in US courts by a team of law professors and students from the Lowenstein International Human Rights Clinic at Yale Law School. Tory Clawson, a law student at Yale, has been immersed in these cases for more than a year. She has visited the people detained at Guantanamo Bay and says their plight raises constitutional due-process and equal-protection concerns.

The detainees haven't been treated the same as fellow Haitians without HIV who were allowed into the US, Ms. Clawson asserts. Moreover, she says, men, women, and children - some of whom are family members without the virus - are being held under conditions described by eyewitnesses as harsh or punitive.

People who move from pre-screening for asylum on to the second, more in-depth round of interviews normally have the help of legal counsel, Clawson explains, since this step can include the summoning of witnesses, presentation of evidence, and numerous appeals. The Haitians being held at Guantanamo Bay had no access to counsel, she says.

The case before the Supreme Court sprang from last May's decision by the Bush administration to stop shipboard screening of Haitians seeking asylum. The camp at Guantanamo Bay was overflowing with those who were found to have a credible fear of persecution, and no other countries in the region had agreed to provide additional havens. At that point the policy of immediate return began - a policy continued by President Clinton despite his campaign promise to end it.

The US Court of Appeals in New York ruled against the government, holding that the Haitians had to be given a chance to explain their reasons for fleeing. But the Supreme Court in August put that ruling on hold pending its own determination of the issue.

Neils Frenzen, an attorney with Public Counsel, a nonprofit law office in Los Angeles, forecasts that "if the Supreme Court says national security is involved, chances are the Haitians will lose." He says the White House, the National Security Council, and the State Department are running Haitian policy - not the Immigration and Naturalization Service.

Another close observer of the cases is Carol Wolchok, who directs the American Bar Association's Center for Immigration Law and Representation. She notes that current law states that the US attorney general "shall not return or deport any alien to a country where his life or freedom may be threatened."

She says the government may claim that the Coast Guard, not the attorney general, is returning the Haitians, but in her view the law's restrictions apply to anyone acting in place of the attorney general.

What's ultimately at stake, Mr. Helton says, is US adherence to international treaties. "This litigation is part of a broader effort to convert what the government considers a policy prerogative into a human rights obligation," he contends.

Stein, on the other hand, argues that a country's primary obligation to police its borders has to take precedence. "No country can take the stand that aliens picked up at sea can demand the right to enter."